Why you really need to wash your workplace drink bottle

That water bottle you refill every day at work is even grubbier than you think it is.

If you're like us at Coach HQ, you have a bottle of water on your desk that you constantly refill, but only rarely wash.

And while it's great to reuse bottles, doctors and hygiene experts say that if you're putting them to your lips, you really ought to wash clean them as often as you would your mug after your cup of tea.

A study of 75 primary school kids' drink bottles found that 13 percent of them failed Canadian safe water drinking tests, with 9 percent exceeding faecal criteria levels and 64 percent exceeding the criteria for safe bacteria, yeast and mould levels.

"When we have a cup of tea or glass of water we wash the glass or mug, so really we should think of drink bottles in the same way," Dr Meredith Arcus, spokesperson for the Royal Australian College of General Practitioners, told Coach.

Rachelle Williams, chair of the Food Safety Information Council, told Coach that while most healthy adults wouldn't get sick from low-level bacteria in a water bottle, if you are immune compromised in any way, it could upset your stomach.

"There is going to be a certain amount of backwash that will contain bacteria and sitting at room temperature it will grow," Williams told Coach.

"There's minimal risk but if you have had a cold [and are immune compromised] then you are more at risk of getting sick from something like that."

Water bottles you drink from should be washed well every day, and if you use a jug of water, a weekly sanitisation is a good idea.

"Rinse your jug daily and once a week, put some white vinegar or lemon juice in it and swish it around the jug – they're mild acids and help kill bacteria to sanitise it," Williams says.

Dr Arcus says the best way to protect yourself from germs is to avoid sharing drink bottles, particularly during flu season.

"We all have bacteria in our mouths and throats and they can be transmitted," she says.

But Dr Arcus says the most important thing for Australians' health is to drink plenty of water to remain hydrated.

"In the hot months it's particularly important that people stay well hydrated," she says.

Glass and metal bottles tend to be easier to clean than plastic ones because they can get nicks and scratches where bacteria can harvest.

A wide-open mouthpiece is also obviously easier to clean than a narrow one.